Re: [stella] 1 cycle!

Subject: Re: [stella] 1 cycle!
From: Thomas Jentzsch <tjentzsch@xxxxxx>
Date: Mon, 17 Mar 2003 22:49:16 +0100
Fabrizio wrote:
> So, any idea on saving up cycles in that function is welcome.. I'm willing
> to use Illegal/Undocumented opcodes too, if required!

No illegal opcodes this time. :-)

You should move the code after BCS DrawBall2 behind JMP X3. This will
save you one cycle in the timing critical path.

For saving more cycles you could merge BallEnableTab and BallShiftTab,
because HMBL and ENABLE can share the bits.

With some shifting you can feed CTRLPF too (but that will cost 2 extra

  lda BallTab,y    ; hhhhsse0
  sta HMBL
  sta ENABL
  ora #5           ; hhsse101
  sta CTRLPF

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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